Consolidate bukkit-utils into the main codebase

[minoneer]

Summary

bukkit-utils was split out as a separate module and published artifact, but in practice it is now tightly coupled to this repository and adds extra module, publishing, and release overhead.

Problem

The current split means:

• another published artifact to version and release
• another module to keep wired into the build and docs
• more release surface for code that is primarily maintained together with uSkyBlock itself

Goal

Evaluate and execute a clean consolidation of bukkit-utils into the main codebase or another clearly internal module layout.

Requirements

• reduce build/release complexity
• preserve internal reuse where it still makes sense
• decide what happens to the currently published artifact
• document any deprecation or migration path if external consumers exist

Notes

This is an internal maintenance issue. The target is simpler ownership and release management, not a user-facing feature.